David Walsh Blog

• By David WalshSeptember 17, 2021

  AggregateError

  One of the big themes of the web these days is concurrency, which leads to accomplishing tasks asynchronously. In doing so, the possibility of multiple errors can occur. Instead of providing a generic error, optimally you'd provide a wealth of error information. TheAggregateError...

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• By David WalshAugust 27, 2021

  jq for JSON

  I old enough to remember when we thought XML was going to change the programming world...then JSON saved us from that hell. Parsing and querying JSON data is fundamental task we've all coded for, but sometimes I just want to get some data locally with minimal...

• By David WalshAugust 23, 2021

  React usePrevious Hook

  Hooks are essential for the functional component pattern in React. One frequent logic comparison with class components was comparing a previous prop value with a current prop value via lifecycle methods. So what's an easy pattern for duplicating previous value comparisons in functional components?The useRef and...

• By David WalshAugust 9, 2021

  Set a Default Node Version with nvm

  As I've shown you in the past, nvm an excellent utility for switching between Node.js versions. Whether your host machine or CI, building and testing your apps on different Node versions is a necessity. I've recently found a few nvm commands that I found really...

• By David WalshAugust 2, 2021

  onInput Event

  Coding HTML forms has been painful my entire career. Form controls look different between operating systems and browsers, coding client side and server side validation is a nightmare, and inevitably you forget something somewhere along the line. Some behaviors don't act the way you'd...

• By David WalshJuly 19, 2021

  Dark Mode in One Line of Code!

  Dark mode has seemingly become the desired visual mode for websites and mobile apps alike. Dark mode is easier on the eyes, especially for those like me who like to burn the midnight oil by coding and reading tutorials. Unfortunately not all websites offer...

• By David WalshJuly 8, 2021

  Fix Seeing “0” in Your JSX Code

  The early days of the web felt like the wild west when it came to coding practices -- just make it work. Then we became enlightened to better practices, separating HTML from CSS and JavaScript. Then came React and JSX, where we combine JavaScript, HTML...

• By David WalshJune 28, 2021

  How to Upload a File via SSH and Command Line

  My preference for daily work is usually GUI applications, like Visual Studio Code for text editing and Cyberduck for remote file server management. I'm also a huge fan of automation, so I do try to learn the command line equivalents of UI functions. My...

• By David WalshJune 21, 2021

  Always Show Arrows for Number Input

  While I enjoy small details that make user interfaces more elegant, I also believe that less is more, especially when it comes to native behavior. One native behavior I dislike is that <input type="number" /> elements only show the increment and decrement arrows when the input...

• By David WalshJune 14, 2021

  Gather Feedback Using the Amazing UserWell

  Most websites and mobile apps collect all sorts of data to try to gain insights into what users are doing, not doing, and to gain insight into what users may want. Those metrics are useful but there's a more valuable way to get information: direct...